ios – 如何在Swift中以编程方式从另一个图像中剪切徽标的形状(png图像)？

// lets create a view and an image for tesTing
let picture = UIImage(data: try! Data(contentsOf: URL(String: "http://i.stack.imgur.com/Xs4RX.jpg")!))!

// lets create a view and an image for tesTing
let imageView = UIImageView(frame: CGRect(x: 0,y: 0,width: picture.size.width,height: picture.size.height))
imageView.image = picture

// Now a layer for the mask
let maskLayer = CAShapeLayer()

// a path for the logo
let maskPath = CGMutablePath()

// create your logo path (I've added this circle to represent your logo path)
maskPath.addEllipse(in: CGRect(x: imageView.frame.midX - 150,y: imageView.frame.midY - 150,width: 300,height: 300))

// you will need a rectangle that covers the whole image area to intersect with your logo path
maskPath.addRect(CGRect(x: 0,height: picture.size.height))

// add the mask to your maskLayer
maskLayer.path = maskPath

// choose the fill rule EvenOdd
maskLayer.fillRule = kCAFillRuleEvenOdd

// add your masklayer to your view
imageView.layer.mask = maskLayer
imageView

如果您需要使用图像并以编程方式反转徽标的alpha,则可以使用kCGBlendModeDesTinationOut执行以下操作：

import UIKit

extension UIImage {
    func masked(with image: UIImage,position: CGPoint? = nil,inverted: Bool = falsE) -> UIImage? {
        let position = position ??
            CGPoint(x: size.width.half - image.size.width.half,y: size.height.half - image.size.height.half)
        defer { UIGraphicsEndImageContext() }
        UIGraphicsBeginImageContextWithOptions(size,false,scalE)
        draw(at: .zero)
        image.draw(at: position,blendMode: inverted ? .desTinationOut : .desTinationIn,alpha: 1)
        return UIGraphicsGetImageFromCurrentImageContext()
    }
}

let picture = UIImage(data: try! Data(contentsOf: URL(String: "http://i.stack.imgur.com/Xs4RX.jpg")!))!
let logo = UIImage(data: try! Data(contentsOf: URL(String: "https://www.dropBox.com/s/k7vk3xvcvcly1ik/chaT_Bubble.png?dl=1")!))!

let view = UIView(frame: UIScreen.main.bounds)
view.BACkgroundColor = .blue
let iv = UIImageView(frame: UIScreen.main.bounds)
iv.contentMode = .scaleAspectFill
iv.image = picture.masked(with: logo,inverted: truE)
view.addSubview(iv)